1. Field of the Invention
The present invention relates to an image recording apparatus which includes a sheet-supply tray device which accommodates a plurality of recording media, a sheet-supply roller which supplies the recording media one by one in a sheet-supply direction, and an image recording device which records an image on each of the supplied recording media.
2. Discussion of Related Art
There has been known an image recording apparatus which employs an image recording device which records an image on a recording sheet as a recording medium supplied from a sheet-supply tray device. The image recording apparatus is realized as an ink-jet printer or a laser printer, or otherwise as a multi-function device (MFD) which has a scanner function and/or a facsimile-machine function as well as a printer function.
The image recording apparatus also includes a sheet-supply tray device which accommodates a plurality of recording sheets as recording media. There is known a sheet-supply tray device of a type which holds recording sheets in a state in which the recording sheets are inclined with respect to a vertical direction; and there is another sheet-supply tray device which holds recording sheets in a state in which the recording sheets are supported horizontally In general, an image recording apparatus in which the recording sheets are conveyed through a straight path tends to adopt a sheet-supply tray device in which recording sheets are supported in an inclined state, while an image recording apparatus in which recording sheets are conveyed through a U-turn path tends to adopt a sheet-supply tray device in which the recording sheets are supported horizontally (for example, as disclosed in JP-A-2005-246907 or JP-A-2005-314067).
Each of the recording sheets accommodated in the sheet-supply tray device is supplied in a predetermined sheet-supply direction by a sheet-supply roller. For example, the sheet-supply roller is arranged to be movable toward, and away from, a tray surface of the sheet-supply tray device via a sheet-supply arm. The sheet-supply arm is pivotable in directions in which the arm moves toward and away from the sheet-supply tray device, and supports the sheet-supply roller rotatably about a rotation s extending in a direction perpendicular to the sheet-supply direction. A drive force from a drive source such as a motor is transmitted to rotate the sheet-supply roller. The sheet-supply arm is biased in a direction in which the sheet-supply roller is pressed on the tray surface of the sheet-supply tray device, by a biasing means such as a weight of the sheet-supply roller or a spring. Since the sheet-supply roller is pressed on the recording sheets accommodated in the sheet-supply tray device, the rotary movement of the sheet-supply roller is reliably transmitted to the recording sheets.
Also, a frictional pad is provided on the tray surface of the sheet-supply tray device, more specifically described, on a portion of the tray surface with which the sheet-supply roller is to come into contact. The frictional pad is made of a material having a frictional coefficient higher than that of the other portion of the tray surface. In this arrangement, a lowermost one of the recording sheets stacked in the sheet-supply tray device is difficult to slide relative to the tray surface. Therefore, in a state in which only a small amount of the recording sheets are left in the sheet-supply tray device, those recording sheets are prevented from being conveyed without being separated from each other
In recent years, a full-color recording has been a function of an image recording apparatus. Therefore, the image recording apparatus is utilized not only for a document printing but for an image printing such as a photograph. In the document printing, recording sheets having A4 size in accordance with Japanese Industrial Standard (JIS) or legal size are often used. In the photograph printing, recording sheets having a size corresponding to a “L-size” printing paper for photographs are often used. In some cases, an image is recorded on a postcard or an envelope each as a recording medium. In addition, in the document printing, ordinary sheets are often used, whereas in the photograph printing, glossy sheets that are coated with a glossy material are often used. Since the image recording apparatus is used for a wide range of purposes, the recording sheets are so selected as to have appropriate sizes and sorts corresponding to the purposes. Therefore, it is needed to change the sizes and/or sorts of the recording sheets to be accommodated in the sheet-supply tray device, depending upon the manner of printing corresponding to each of the purposes.
For example, in a case in which ordinary sheets of A4 size which are often used in the document printing are accommodated in the sheet-supply tray device, an auxiliary tray may be provided in the image recording apparatus so that the auxiliary tray accommodates L-size glossy sheets which are often used in the photograph printing. However, it is needed to provide a sheet-convey path between the auxiliary tray and the image printing device and employ a sheet-supply roller corresponding to the auxiliary tray. This leads to increasing the size of the image recording apparatus and the cost of manufacture thereof.